Derating factors for Cable trays with cover

Former Community Member over 5 years ago

“Ampacity of cables in covered tray" developed by Engmann concluded that the ampacities of cables in ventilated trays with cover are 70% to 75% of the open-top tray ampacities .

I can't find such derating factors in BS 7671 neither in IEC 60364-5-52. Please clarify.

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0 Former Community Member over 5 years ago

They aren't published in BS 7671 - and there are a variety of methods of lidding including ventilated and unventilated - which perhaps explains why

Whilst ampacity reduction to 75% is fairly normal, when tested, it's often less as the flat steel cover is quite a good radiant emitter

I don't think you'll find definitive published derating factors, this is very much one for the engineer to make a judgement

Regards

OMS
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0 Former Community Member over 5 years ago

They aren't published in BS 7671 - and there are a variety of methods of lidding including ventilated and unventilated - which perhaps explains why

Whilst ampacity reduction to 75% is fairly normal, when tested, it's often less as the flat steel cover is quite a good radiant emitter

I don't think you'll find definitive published derating factors, this is very much one for the engineer to make a judgement

Regards

OMS
Cancel
Vote Up 0 Vote Down

Cancel

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Derating factors for Cable trays with cover

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